检索结果-内蒙古大学图书馆

6th WASE International Conference on Information Engineering, ICIE 2017

作者： Zhao, Pei Yan Qin, Ji Dong Peng, Hua Feng National Key Laboratory of Science and Technology on Blind Signal Processing P.O. Box 610041 China Zhengzhou Institute of Information Science and Technology P.O. Box 450001 China

ISBN: (纸本)9781450352109

This paper1 presents an accuracy analysis of Time Delay Estimation (TDE) in the passive location system. Firstly, the signal processing model using the information of envelope and phase are presented, respectively. Then the Cramer-Rao Lower Bounds (CRLB) for phase delay estimation is developed. The bound is shown to be inversely proportional to carrier wavelength, and for narrowband signals, independent of the signals bandwidth. Simulation results show that the theoretical analysis is correct, and the use of phase information alone or in combination with the envelope information is expected to significantly improve the accuracy of time delay estimation. © 2017 Copyright held by the owner/author(s).

关键词： Timing circuits

来源：评论

学校读者我要写书评

暂无评论

The Application of HBF in Small Aperture OTHR

The Application of HBF in Small Aperture OTHR

引用

International Congress on Image and signal processing

作者： Yu Jia Qing He Lai Yuan Luo National Key Laboratory of Science and Technology on Blind Signal Processing

ISBN: (纸本)9781467390996

Due to the decrease of azimuth resolution and array gain, the performance of small aperture over the horizon radar (OTHR) is not as good as the conventional OTHR. Therefore, it is necessary to find a new method to improve array performance of small aperture OTHR to satisfy the requirements of target detection. In this paper, conclusions on the performance losses are obtained by deducing the expression of signal to clutter ratio (SCR) under small aperture OTHR receiving condition. Based on the conclusions, Hyper Beam, which is derived from sonar array processing, are applied to improve the performance of small aperture OTHR. Eventually, experimental simulations are given to verify our conclusions.

关键词： HBF Small aperture OTHR UCA SCR UCA Thyristors Fetal Hemoglobin apertures azimuth resolution Object detection

来源：评论

学校读者我要写书评

暂无评论

Direct Position Determination by Double Fixed Station Based on Delay and AOA

Direct Position Determination by Double Fixed Station Based ...

引用

2017 2nd International Conference on Control, Automation and Artificial Intelligence(CAAI2017)

作者： Xiangyu Liu Qing He Zhengbo Sun National Key Laboratory of Science and Technology on Blind Signal Processing

ISBN: (纸本)9781510845541

To improve location accuracy, a single-step localization algorithm by double fixed station, using the thought of "signal to position" is proposed to solve the problem of two-step conventional method's information loss, since two-step conventional method divides in estimating intermediate parameter and geolocation. First, the observed signal model is analyzed and problem's mathematical model is generalized. Next, the cost function is formulated based on maximum likelihood estimator(MLE) and simplified as the maximal eigenvalue of hermite matrix. Then, the geographical location maps in twodimensional sector-grid based on angel of arrival(AOA), afterward, the algorithm process is introduced. Finally, simulation results demonstrated that the proposed DPD algorithm outperforms the two-step conventional algorithm in location accuracy, and when signal to noise ratio(SNR) of the same observed signals is-5 dB, the root mean squared error(RMSE) of proposed algorithm reduce the errors of 47% in typical scene.

关键词： passive localization direct position determination(DPD) maximum likelihood estimator(MLE) passive localization time delay angel of arrival(AOA)

来源：评论

学校读者我要写书评

暂无评论

Low Altitude, Slow Speed and Small Size Object Detection Improvement in Noise Conditions Based on Mixed Training

Low Altitude, Slow Speed and Small Size Object Detection Imp...

引用

2018 3rd International Conference on Communication,Image and signal processing（CCISP 2018）

作者： J.F.Que H.F.Peng J.Y.Xiong National Key Laboratory of Science and Technology on Blind Signal Processing

The low altitude, slow speed and small size object which we call LSS-object for short, such as small UAV(unmanned aerial vehicles) have become a hot issue of air defense security, which is difficult to detect and identify accurately from the image. In this paper, aiming at the problem of LSS-object detection under noise environment, the detection method based on deep learning is proposed. Firstly, a standard training dataset consisting 5 classes of typical objects is constructed. Then, the standard dataset is augmented with noise of different intensity. Finally, YOLO v3 algorithm is used to form a LSS-object detection system which can adapt to environment noise. The training and detection experiments were carried out on the GPU server. After only using the noise-free dataset for training, the mAP(mean Average Precision) of the noise-free test set detection reached 81.07%, but the mAP decreased to 20.68% when the noise variance was *** adopting the mixed training strategy of the dataset with noise variance of 0.01 and noise-free data, the mAP for the test set detection with noise variance of 0.03 was increased to 70.61%, and the mAP still reached 79.85% in noise-free test set detection. The experiment results show that the mixed training strategy can greatly improve the accuracy in the noisy images detection while maintaining a higher accuracy in noise-free images.

关键词： image LSS Low Altitude Slow Speed and Small Size Object Detection Improvement in Noise Conditions Based on Mixed Training Object

来源：评论

学校读者我要写书评

暂无评论

Freshet Method for Wideband Spectrum Sensing

Freshet Method for Wideband Spectrum Sensing

引用

2016 International Conference on Computer Engineering,Information science and Internet technology(CII 2016)

作者： CHUANDANG LIU LUXI LU JIAN CHENG National Key Laboratory of Science and Technology on Blind Signal Processing

This paper presents a new method for automatic wireless spectrum segmentation. Spectrum segmentation is regarded as the first step to extract signals of interest in wideband spectrum, and it aims to identify the boundaries between sub-band signals. The proposed Freshet Method, based on the Power Spectral Density(PSD) quantization and Connected Components(CC) detection, is designed for a better spectrum segmentation performance. This method is validated on satellite signals, and the testing result shows a better accuracy of the sub-band boundary estimation than the other published methods.

关键词： PSD Matrix Freshet Method for Wideband Spectrum Sensing

来源：评论

学校读者我要写书评

暂无评论

Reconstruct LDPC Codes in a Noisy Environment

Reconstruct LDPC Codes in a Noisy Environment

引用

2015 IEEE International Conference on Progress in Informatics and Computing(PIC 2015)

作者： Xin Bao Yuanling Huang Guiliang Wang National Key Laboratory of Science and Technology on Blind Signal Processing

Focus on the problem of reconstructing LDPC codes in a noisy environment, an algorithm based on Column Elimination Operation, Parity-Check Vector Judgment Criterion and Gradual Row Transformation is proposed, which is used to blind recognize LDPC codes. This algorithm first gets enough dual vectors of the receive codes, then selects real parity-check vectors of the dual-space of LDPC codes, and then, detectives and deletes the error code words. The above steps are iteratively carried out until the original problem is reduced to an easier problem, i.e., blind recognition LDPC codes in an error-free context, and finally obtain the sparse parity-check matrix by using Gradual Row Transformation. The simulation and experiment results show that, this algorithm fits most of LDPC standards, including 802.16 e, 802.11 n, DVB-S2, GJB7296, GB20600, etc., and it is an effective solution for LDPC codes blind recognition in a noisy environment.

关键词： channel coding LDPC codes blind recognition error bit

来源：评论

学校读者我要写书评

暂无评论

A conditional-probability zone transformation coding method for categorical features 19

A conditional-probability zone transformation coding method ...

引用

2019 ACM Turing Celebration Conference - China, ACM TURC 2019

作者： He, Liang Shen, Chao Li, Yun National Key Laboratory of Science and Technology on Blind Signal Processing Chengdu Sichuan China MOE Key Lab for Intelligent Networks and Network Security Xi'an Jiaotong University Shaanxi Xi'an China

ISBN: (纸本)9781450371582

It has been a key issue for solving problems efficiently by machine learning models with code categorical features. The state-of-the-art one-hot coding is a widely accepted method to convert the categorical features into numerical values. However, it attracts a sparse space and meaningless value after coding. We come up with a novel coding method based on conditional probability after dividing the features into zones, which is called Conditional-probability-based Zone Transformation (CZT) coding. CZT coding calculates the conditional probability of each feature, then divides the features into several zones according to the probability and finally codes the features in each zone. We mathematically prove that compared with the state-of-the-art method, CZT coding reduces the code length by at least the mean of feature space and the issue becomes into an easier one after CZT coding for the following machine learning model. Finally, using the same neuron network as the classifier, we compare the performance of CZT coding and one-hot coding by using the titanic dataset, where most of the features are categorical, and the result is that CZT coding makes the classifier performs better both on the accuracy and steadiness. © 2019 Association for Computing Machinery.

关键词： Probability

来源：评论

学校读者我要写书评

暂无评论

ASTF: Visual Abstractions of Time-Varying Patterns in Radio signals

引用

IEEE Transactions on Visualization and Computer Graphics 2023年第1期29卷 214-224页

作者： Zhao, Ying Ge, Luhao Xie, Huixuan Bai, Genghuai Zhang, Zhao Wei, Qiang Lin, Yun Liu, Yuchao Zhou, Fangfang School of Computer Science and Engineering Central South University Changsha China National Key Laboratory of Science and Technology on Blind Signal Processing Chengdu China College of Information and Communication Engineering Harbin Engineering University Harbin China China Research Institute of Radiowave Propagation Qingdao China

A time-frequency diagram is a commonly used visualization for observing the time-frequency distribution of radio signals and analyzing their time-varying patterns of communication states in radio monitoring and management. While it excels when performing short-term signal analyses, it becomes inadaptable for long-term signal analyses because it cannot adequately depict signal time-varying patterns in a large time span on a space-limited screen. This research thus presents an abstract signal time-frequency (ASTF) diagram to address this problem. In the diagram design, a visual abstraction method is proposed to visually encode signal communication state changes in time slices. A time segmentation algorithm is proposed to divide a large time span into time slices. Three new quantified metrics and a loss function are defined to ensure the preservation of important time-varying information in the time segmentation. An algorithm performance experiment and a user study are conducted to evaluate the effectiveness of the diagram for long-term signal analyses. © 2022 IEEE.

关键词： Data visualization

来源：评论

学校读者我要写书评

暂无评论

A Self-Adaptive Modified Whale Optimization Algorithm for Optimizing the Linear Antenna Array

A Self-Adaptive Modified Whale Optimization Algorithm for Op...

引用

International Conference on Measuring technology and Mechatronics Automation, ICMTMA

作者： Wentao Feng Kekang Song National Key Laboratory of Science and Technology on Blind Signal Processing Chengdu China National Key Laboratory of Science and Technology on Blind Signal Processing Sichuan Chengdu China

ISBN: (数字)9781728170817

ISBN: (纸本)9781728170824

The whale optimization algorithm (WOA) is an effective algorithm for solving complex optimization problem. Its unique search mechanism results in better exploitation than exploration capability which means that it's easy to get trapped in the local optima. A self-adaptive modified whale optimization algorithm named of SAMWOA is proposed. A self-adaptive quasi-opposition method and novel population updating mechanism is integrated into the whale optimization algorithm to improve the solution accuracy. Finally, the proposed algorithm is utilized in optimizing the radiation pattern of a 16-element linear antenna array. The experimental results show that SAMWOA algorithm can reduce the sidelobe level obviously.

关键词：

来源：评论

学校读者我要写书评

暂无评论

An image co-registration method for wide-swath and high-resolution spaceborne InSAR

An image co-registration method for wide-swath and high-reso...

引用

2009 Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2009

作者： Wang, Ping Li, Zhenfang Suo, Zhiyong Liu, Yanyang National Key Laboratory of Science and Technology on Radar Signal Processing Xidian University Xi'an 710071 China

ISBN: (纸本)9781424427314

In this paper, we analyse the issue of SAR image co-registration for wide-swath and high-resolution spaceborne InSAR. A solution to this problem is proposed in which three processing procedures are adopted. First, image co-registration pre-processing is performed. There are two methods for this step: one is based on InSAR orbit and radar system parameters, and the other is based on the cross-correlation information of the master and the slave image. Second, coarse co-registration is implemented by block processing. Finally, fine co-registration is executed in order to obtain sub-pixel co-registration accuracy. Data simulation and qualitative analysis of coherence show that this method can provide accurate co-registration for wide-swath and high-resolution spaceborne InSAR, and meet the practical engineering requirement. ©2009 IEEE.

关键词： Synthetic aperture radar

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：